PHOENIX — Jacob deGrom is the strong front-runner to win the NL Rookie of the Year award Monday night, but maybe even that assessment is an understatement.

“He’s a lock,” former Mets pitcher Ron Darling said.

DeGrom, the Mets right-hander, last week was named a finalist for the award along with Reds outfielder Billy Hamilton and Cardinals second baseman Kolten Wong.

The Mets haven’t had a Rookie of the Year since 1984, when Dwight Gooden won the award. Darryl Strawberry (1983), Jon Matlack (1972) and Tom Seaver (1967) are the other Mets to have won NL Rookie of the Year.

DeGrom’s résumé includes a 9-6 record and 2.69 ERA with 144 strikeouts and 43 walks in 140 ¹/₃ innings.

Hamilton stole 56 bases in 79 attempts this season, but also had a mediocre slash line of .250/.292/.355 with six homers and 48 RBIs.

Wong had a slash line of .249/.292/.388 with 12 homers and 42 RBIs. Though he had three homers and six RBIs for the Cardinals in the postseason, those numbers do not factor into Rookie of the Year consideration.

Darling, a SNY analyst, said he was most impressed with the 26-year-old deGrom’s composure after arriving from Triple-A Las Vegas in May.

“For a rookie pitcher to overcome not winning in his first eight starts and to pitch so well with runners on base and handle himself at the plate and in the field is impressive,” Darling said.

“Those usually come with time and he handled it with such aplomb. You would be hard-pressed to think he’s just a rookie, the way he handled himself. He just has a maturity that not many young pitchers have.”

The Mets called up deGrom with the idea he would pitch from the bullpen, but an injury to Dillon Gee changed those plans.

“He was brought up with Rafael Montero, on the same day, and the thought was by most people was that Montero was a little higher in the pecking order than deGrom,” Darling said.

“And I think it really reveals a lot about young pitching is that when they get to the bigger stage, some like Rafael are going to take a little more seasoning and then you get some like Jacob, when they hit the big time they just blossom. Some wilt and some blossom and deGrom blossomed.”